Question

10.
Three long straight parallel charge lines are kept horizontally as shown in the figure. For what sign and magnitude
of linear charge density 2 will the net electric field be zero at points (i) A and (ii) B.
​

Answer 1

E=kQ/r^2 where k is a constant with a value of 8.99×10^9 N m^2/C^2.

You should use this formula for your question.